1. Technical Field of the Invention
The present invention relates to a dual function antenna structure and, more particularly, relates to a primary antenna element which resembles a secondary antenna element when operating in a second mode.
2. Description of the Related Art
Portable electronic radio equipment are typically desired for their small size and portable convenience. Typically, a single small antenna structure, such as a telescoping dipole or monopole antenna, is common. Nevertheless, these and other known antennas accommodate only one mode of operation. For example, these antennas are not optimized to resonate at two different radio frequencies.
Furthermore, these antennas accommodate radio frequency energy of only one type of polarization. For example, the telescoping monopole antenna of a typical cellular radiotelephone today accommodates only linearly polarized radio frequency energy. Compact antenna structures capable of providing a dual function of selected linearly polarized and circularly polarized radio frequency energy are unknown in the art.